The broad objectives of the proposed research are to measure cancer incidence and mortality in a cohort of farm workers in California (N=139,000) and to conduct nested case-control studies within the cohort in order to evaluate the association between work involving pesticide exposures and cancer risk. The objectives of this study will be accomplished using a variety of epidemiologic study designs. A computerized record linkage will be conducted between a roster of a largely Hispanic farm worker union (the United Farm Workers of America or the UFW) and the database of the California Cancer Registry (CCR) the population-based cancer registry which has monitored cancer incidence and mortality in California since 1988. Upon completion of the record linkages for both newly diagnosed cancers (1988-2000) and cancer deaths (1973-2000), risk of cancer for specific types of cancer will be evaluated in the UFW by calculating morbidity/mortality odds ratios using the California Hispanic population as the reference. In addition, variables such as stage and grade of disease at diagnosis, and histologic subtype of cancer will be evaluated, again comparing the experience of UFW members with cancer to the cancer experience of the California Hispanic population. After completion of the initial descriptive analyses, nested case-control studies will be conducted for several types of cancer including leukemia, brain, stomach and cervix cancer. Specifically, for each cancer case diagnosed among the membership of the UFW, incidence density controls will be selected form the remainder of the cohort. Occupational histories, including the nature of the crops and commodities in which individual cases and controls worked will be used as the exposure variables of interest. Data from the California Department of Pesticide Regulation (DPR) will also be used to construct lob exposure matrices (JEM) for both cases and controls. Adjusted odds ratios will be calculated for several cancer sites evaluating particular pesticide exposure profiles as well as length of work in particular crops and commodities. Survival analyses will also be completed comparing the five-year relative survival of cancer in the UFW to the California Hispanic population.